As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
NVIDIA Scalable Link Interface (SLI) is a technology for linking together graphics processing units (GPUs) of multiple video card boards to employ parallel processing to produce a single video output having scaled-up graphics performance from the linked GPUs. FIG. 1A illustrates a simplified side cross-sectional view of the stackup of a conventional SLI architecture 100 that has been implemented in the past to link two modular graphics boards (printed circuit boards) 102a and 102b within a notebook computer chassis having a width of at least 17 inches. Each of the two graphics boards 102a and 102b includes a graphics processing unit (GPU) not shown in FIG. 1A, and is mounted to the same side of a main motherboard 104 of the notebook computer. As shown, each of graphics boards 102a and 102b is also mechanically mounted in the same plane (or at the same level) as the other graphics board, and the plane of both graphics boards 102a and 102b is mounted parallel to the plane of the motherboard 104.
Still referring to FIG. 1A, the circuitry and GPU of each graphics board 102a and 102b is electrically linked to circuitry and a central processing unit (CPU) 125 on the motherboard 104 through a separate respective mobile peripheral component interconnect express (PCIe) module (MXM) connector (socket) 106a or 106b as shown. For purposes of illustration, the graphics boards 102, MXM connectors 106 and main motherboard 104 are shown in exploded view with respect to each other to illustrate the signals communicated therebetween. As shown, each of MXM connectors 106a and 106b transfers electrical signals 111 (including graphics board power supply, PCIe bus signals) between the CPU 125 of motherboard 104 and a respective GPU of one of graphics boards 102a and 102b. As further shown in FIG. 1, each of graphics boards 102a and 102b is also mechanically mounted to the motherboard 104 by one of the MXM connectors 106. A thermal cooling module 107c including a heat sink is mechanically mounted in a thermally-conductive manner to the CPU 125 on motherboard 104, which is located in the motherboard area between the two graphics boards 102a and 102b. The thermal cooling module 107c is provided for cooling the CPU 125 of the motherboard 104. Separate thermal cooling modules 107a and 107b including separate heat sinks are mechanically coupled in a thermally-conductive manner to cool the respective separate GPUs of graphics boards 102a and 102b. Each of the separate thermal cooling modules 107 are isolated from, and operate separately from, the other thermal cooling modules 107 as further described below in relation to FIGS. 1B and 1C.
In the conventional configuration of FIG. 1A, motherboard 104 has a side-to-side width (CWM) that supports the two MXM connectors 106a and 106b in position for connection to the respective graphics boards 102a and 102b. As shown, graphics boards 102a and 102b have respective board widths (CWGGA) and (CWGGB), and a space (CSP) exists between the two graphics boards 102a and 102b to accommodate heat sink of thermal module 107c. A SLI bridge cable 103 is provided to span the space (SP) to interconnect the graphics boards 102a and 102b in master-slave relationship as shown. SLI bridge cable 103 transfers inter-graphics board signals 121 (multiuse Input/Output Interface signals) between the graphics boards 102a and 102b. The GPU of the master graphics board 102a provides output video signals 131 (such as HDMI, DVI, or SVGA) to an attached display device (such as LED or LCD display device).
FIG. 1B illustrates an underside view of a notebook computer chassis 175 of a notebook computer that contains a conventional SLI architecture 100 received in the bottom portion of the notebook computer chassis. As shown, three separate heat pipe sets 160a. 160b and 160c are provided and coupled to the separate heat sinks (indicated by dashed outline) of separate thermal modules 107a. 107b and 107c, respectively. Each of the separate heat pipe sets 160a. 160b and 160c is coupled between a single heat sink and a single separate conductive block that is cooled by a separate cooling fan 182a, 182b or 182c, respectively. Thus, the processor of each of graphics boards 102a, 102b and CPU 125 of motherboard 104 is cooled by a separate cooling system (i.e., thermal cooling module/heat sink, heat pipe set, conductive block and cooling fan) that is completely separate from the cooling systems that is used to cool the other processors, i.e., requiring a total of three separate cooling systems. In this regard, FIG. 1C illustrates an overhead view of the conventional SLI architecture 100 of FIG. 1B, in which the three separate cooling fans 182a, 182b and 182c are visible on top of motherboard 104.
Referring again to FIG. 1B, a projective PCB area of the conventional SLI architecture 100 of FIG. 1B is a surface area defined by the outermost boundary edges of motherboard 104 that exist within the width (CWM) and depth (CDM) of motherboard 104 that is employed to support the graphics board PCB components 102a and 102b and needed circuitry as shown, i.e., conventional projective PCB area=CWM×CDM. In this regard, the outer dimensions of motherboard 104 is large enough so that graphics boards 102a and 102b lie completely within the outer boundaries of motherboard 104 when stacked on top of the motherboard 104. Conventional MXM-compatible graphics cards 102a and 102b (up to 100 watts maximum) each has outer dimensions of 105 millimeters wide×82 millimeters deep, and a conventional motherboard 104 employed to support two conventional side-by-side MXM-compatible graphics cards 102a and 102b has outer dimensions (CWM) of 436.8 millimeters wide×158 millimeters deep that define a projective PCB area. Overall stack height of the conventional SLI architecture 100 of FIGS. 1A-1C between (and including) thermal modules 107a/107b/107c as well as graphics cards 102a/102b and motherboard 104 ranges from 30 millimeters to 50 millimeters at different points in the stackup of FIGS. 1A-1C. In another conventional SLI architecture, a narrowed “neck” section of the motherboard (i.e., having a neck width of 240 millimeters) has been utilized that allows room for cooling fans to be positioned on either side of the motherboard with the narrowed 240 millimeter-wide neck area positioned therebetween.
A 17-inch wide notebook computer chassis or larger is required to contain the outer dimensions and projective PCB area of the conventional SLI architecture 100 of FIGS. 1A-1C, which requires a motherboard 104 to bear the MXM connector sockets 106. Moreover, due to the relatively large projective PCB area corresponding to the large area of motherboard 104 that is required to support the dual graphics boards 102a and 102b, available space within a chassis enclosure for the system thermal solution is limited. Additionally, the maximum useable size of cooling system fans and graphics boards are limited for a given chassis enclosure size. In this regard, graphics boards 102 are limited to 100 watts maximum power for a 17-inch wide notebook computer installation. A further increase in motherboard projective PCB area and notebook chassis size may be required if power of graphics boards 102 is increased above 100 watts and/or larger cooling fans are desired. Further, three separate individual cooling systems are employed to separately cool each of the three respective separate processors (CPU and two GPUs) of conventional SLI architecture 100 due to the relatively large distance between the three processors (CPU and two GPUs) and effective heat pipe length limitations, which results in a complicated thermal solution that is relatively difficult to maintain.